Microstructure, phase transformation and mechanical properties of NiMnGa particles/Cu composites fabricated by SPS
(1. Institute of Materials Processing and Intelligent Manufacturing, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China;
2. Sunrui Marine Environment Engineering Co., Ltd., Qingdao 266101, China)
2. Sunrui Marine Environment Engineering Co., Ltd., Qingdao 266101, China)
Abstract: Microstructure, phase transformation and mechanical properties of NiMnGa particles/Cu composites prepared by spark plasma sintering method were investigated by SEM, EDS, XRD, susceptibility measurements and mechanical tests. The NiMnGa particles were found to react with Cu matrix and the composites exhibited a similar crystal structure to the Cu matrix. The martensitic transformation and Curie transition of the composites were weakened due to the composition change of NiMnGa particles caused by reactions. With increasing NiMnGa particles content, the martensitic transformation and Curie transition of the composites were enhanced to some extent. However, the martensitic transformation temperature and Curie transition temperature were decreased by ~50 K as compared to those of the original NiMnGa particles. The compressive strength of the composites increased with the increase of NiMnGa particles content, whereas the compressive strain was decreased gradually.
Key words: NiMnGa alloys; Cu composites; spark plasma sintering; microstructure; phase transformation; mechanical properties